Vaulty is registered in the Oxford English Dictionary as:"resembling a vault; having the arching form of a vault". The word "vault" itself entered english via the french "voute" which itself stems from the Latin "volvere," namely "to turn".

Assuming the name was taken from a German gal, it was probably originally pronounced "Fawlty," as in evetyone's favorite resort in Torquay :)

German : Will you stop talking about the war!Basil : Me? You started it!German : We did not start it.Basil : Yes you did, you invaded Poland...